Oddities, musings and news from the health world

Another thing you love that probably causes cancer

An international group of scientists has linked hot tea with esophageal cancer, according to a new study. The problem doesn’t appear to be the tea itself, but the temperature at which it is consumed.

Residents of Golestan province in northern Iran have one of the highest rates of esophageal squamous cell carcinoma in the world. They don’t drink alcohol or smoke –- the two primary risk factors for the disease in the West –- but they do consume tea. Lots of it. Nearly 1.2 liters per day, on average. So local researchers set out looking for a connection.

They recruited 300 esophageal cancer patients who were diagnosed at the only gastrointestinal specialty clinic in the eastern part of Golestan and matched them up with 571 healthy controls who shared their age, gender and place of residence. All but one of them drank tea, and they gave interviewers information about their tea consumption and brewing habits.

Teaming up with investigators from the U.S., England, France and Sweden, the researchers calculated that people who said they drank “hot” tea (149 to 156 degrees Fahrenheit) were more than twice as likely to develop esophageal cancer as people who said they drank the beverage “warm” or “lukewarm” (less than 140 degrees). Those who said they took their tea “very hot” (at least 158 degrees) were more than eight times as likely to get esophageal cancer, according to the study, published online today by BMJ, formerly the British Medical Journal.

The researchers also asked people how long they waited to drink their tea after pouring it. Those who said they waited two to three minutes were nearly 2.5 times more likely to develop the cancer compared with people who said they waited at least four minutes. Impatient tea drinkers who waited less than two minutes were 5.4 times as likely to be diagnosed with esophageal cancer, the study found.

The study didn’t assess the mechanism linking hot tea to esophageal cancer, but the researchers said the temperature of the liquid was almost certainly to blame rather than the compounds in the tea itself.

In an editorial accompanying the study, David Whiteman of the Queensland Institute of Medical Research in Brisbane, Australia, advised tea drinkers in Iran and elsewhere to simply exercise some patience before enjoying their favorite beverage.

“It is difficult to imagine any adverse consequences of waiting at least four minutes before drinking a cup of freshly boiled tea, or more generally allowing foods and beverages to cool from ‘scalding’ to ‘tolerable’ before swallowing,” he wrote.